THE INFLUENCE OF AMOUNT AND BEAM DIRECTION BETWEEN CLINICAL TARGET VOLUME (CTV) AND PLANNING TARGET VOLUME (PTV) OF MARGIN DETERMINATION

• Main Author: NURHANIVAH (NIM : 10212071), DEVI
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/21676
• Institution: Institut Teknologi Bandung

One of the radiotherapy stages is Treatment Planning System (TPS), which includes the process of margin determination to ensure that the dose is adequately delivered. This research was conducted to determine the margin between Clinnical Target Volume (CTV) and Planning Target Volume (PTV). CTV-PTV margin is the area that is likely to change due to the uncertainty of the geometry, which includes systematic and random deviations. Several hospitals use 1 cm of CTV-PTV margin without any calculations. Therefore, this study was aimed to investigate CTV-PTV margin influenced by the number and the direction of electron beams. The results would be used to make the dose distribution using finite difference method and dose calculation. This study used one to four radiation angles which were arranged in opposite direction and arbitrary direction. The results showed that the range of CTV-PTV margin was 0.01-0.47 cm and the CTV-PTV margin that was generated from the three beams direction was better than the others because it received 100% dose, while the dose recommended by ICRU 50 was about 90-107%.